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Back in the 1960’s, we designed and built our first chemical storage tanks from thermoplastic sheets. At this time alternative materials and formats were still in development, but basic principles will tell you that using flat sheet to create storage tank cylinders comes with challenges. And these challenges become even greater when the tank has a large capacity.

Over the last 60 years we’ve seen a steady trend and increased demand from the market for large capacity tanks. Customers are driving to improve efficiencies and performance, with pressures on available site space, the need to make operational savings and improve environmental credentials. Larger tanks not only give the obvious increased capacity but require fewer tanker deliveries therefore lowering costs and associated emission levels.

Manufactured to your exact specifications

A large volume of any liquid will generate a high level of hydrostatic load, the outward force put on the walls of the containing vessel by the liquid. These load levels concentrate in the vessel’s lower regions and so to ensure safe containment, walls of a specific thickness are required. The British and European Standard (BS EN 12573:2000) for manufacturing chemical storage tanks demands the wall thickness to be built up of no more than 2 sheets, so a thick tank wall will demand working with thick sheet, which is very hard to coax into a curve. Welding the 2 sheets together then also generates potential weak points and leak paths, neither of which are desirable when storing aggressive chemicals.

Technological advancement beyond using sheet is to manufacture chemical storage tanks using the spiral wound manufacturing method, which extrudes a strip of thermoplastic to give a homogenous cylinder without the potential weak weld points or leak paths using sheet involves. This method of manufacture also allows the exact wall thickness required to withstand the hydrostatic load to be created as well as the precise tank diameter and height needed to maximise the use of available site space.

Large capacity and long design life

The spiral wound manufacturing method was developed back in the 1990’s by Chem Resist and Cambridge University and allows us to manufacture chemical storage tanks to any diameter between 950mm and 4200mm to suit available footprint and with capacities up to 125,000l (90,000l for a bunded tanks) with a single homogenous cylinder structure. Every Chem Resist tank is supplied without any limitations on its number of fill and empty cycles, which over their 20 year design life can total a very large capacity indeed!

If you’d like to discuss your chemical storage applications and large capacity requirements, please contact us or call 01924 499466